I am to acknolege the reciept of your favor of Mar. 13. & to thank you for the trouble you have taken. the result of your observations [impress] me strongly with the belief that the person on whose account I [wrote] to you will be disappointed in his supposed discovery. however he has still hopes, and wishes me to ask you to take the trouble of trying again under certain precautions, which, as I do not understand them well, I will quote in the very words of his letter. ‘I find you did not give Bishop Madison any directions respecting the elevation of the needle, but I wish him to make a second trial with his dipping needle, & to be governed by the directions; first, let the horizontal motion be confined, so that the instrument may be placed either North or South, East or West then let the needle be placed East & West and brought to nearly a true balance, the North end rather the heaviest. then turn the South end of the needle to the true North point. let attention be paid to the degree of elevation on the arch where the needle is checked by the polar attraction. the South virtue of the magnet being much inferior in strength to that of the North that it’s power except when very highly touched is not equal to hold the needle stationary for more than 30. seconds of time but the magnetic check is easily perceived.’

I expect to remain here 3. or 4. weeks still, within which time shall be happy to recieve the result of the trials above proposed, as also your own essay on magnetic attraction if ready. I have never published any thing relative to the Mammoth except what is in the Notes of Virginia. I have given the Philosophical society a paper on the subject of the bones of another enormous animal of perhaps the Lion kind, whom I have called the Megalonyx. these bones were sent to me from Greenbriar, and deposited with the society, in whose volume now in press the account will appear. I have so nearly overrun the moment of the post that I must here end with my friendly salutations.